Sorbic acid, also named as Sorbicacid in English, is a kind of unsaturated fatty acid. Sorbic acid is also known as parasorbic acid, 2, 4-hexadienoic acid and 2-propenyl acrylic acid. Sorbic acid is colorless acicular or white powder crystalline, odorless or with slight stimulus odor, light resistant and heat resistant. Potassium sorbate is formed by the chemical reaction between sorbic acid and potassium carbonate which are the raw materials, wherein sorbic acid radical is bonded with potassium ion to form potassium sorbate. Potassium sorbate is white to light yellow flaky crystalline, crystal particle or crystal powder, is odorless or with slight odor, and is easy to absorb moisture and discolor by oxidative decomposition when exposed to air for a long time. Sorbic acid is insoluble in water but is easily soluble in organic solvents such as ethanol, etc., whereas potassium sorbate is very soluble in water as well as in high concentration sucrose and salt solutions, so potassium sorbate is widely used in production. Sorbic acid is an unsaturated acid having 6 carbon atoms. Generally, the commercially available potassium sorbate is white or light yellow particles with a content of 98%-100%. It is odorless or with slight odor, easy to absorb moisture and be oxidized into brown, and stable to light and heat. Its relative density is 1.363, and its melting point is 270° C. with decomposition, and the pH value of the solution with 1% of potassium sorbate is 7-8.
There is a need to develop the powder granulation technique in powder industry production. In different industry fields, powder is often used as an intermediate process of production. But in the production process using powder, there are always many disadvantageous factors such as poor fluidity of powder, difficulties in measurement, dust emission, and difficulties in preservation and transportation, etc. Therefore, the method and process for making powder into particles are applied more and more broadly because of overcoming these disadvantages. Therefore, in order to apply potassium sorbate to various products, it is required to make potassium sorbate into particles.
Chinese patent No. CN103351294A discloses a method of preparing potassium sorbate. The preparation method generally granulates after mixing the dried potassium sorbate powder with potassium sorbate solution during granulation, increasing the binding force, reducing the contact with products by staffs, improving the security of product quality, and making the granulation effect better.
After mixing potassium sorbate powder particles with water, a liquid-bridging force can be formed between particles, but this force is not sufficient to ensure that two powder particles are capable of binding with each other to roll at a high speed. During spheronization, the extruded material will break the powder particles that were bound together originally, while the binding effect of particles will in turn affect the breaking effect of the material. Therefore, there is a need for a method of producing potassium sorbate particles which has the following benefits: an appropriate binding effect of the powder particles, a good breaking effect and a good spheronization effect, and uniformity of granulation.